[Laser] off topic
James Whitfield
n5gui at cox.net
Mon Jun 2 15:57:59 EDT 2008
Ahhh. Interesting idea. Sounds like a row of three or more Lambertian LEDs
would work, each could have the angle trimmed some to cover more area than
if they were all parallel. Such a light bar could be one long string, two
or three vertical rows, or a cluster.
It seems you may be wanting more light that you can get from the available
LED flashlights. If so it may be approaching the cost and weight of a motor
cycle headlamp, which also incurs the hefty weight of a battery to power it.
I hope that the ideas help you.
Best Wishes.
James
n5gui
----- Original Message -----
From: <riese-k3djc at juno.com>
To: <laser at mailman.qth.net>
Sent: Monday, June 02, 2008 2:27 PM
Subject: Re: [Laser] off topic
>
> I was looking to mount several of the H Power diodes on /in a piece of
> PVC
> and fix that to the handle bar,, I need a wide band of light with lots of
> spill
> over so reusing an existing head lamp housing,, which I dont have ,, isnt
> going to work. With my night vision not so great just a bright spot
> on the trail is exhausting to use,, with the NMHD and better batteries
> at good prices i figure several hours if use should be avaible so I need
> a wide
> spill of light
>
> Bob K3DJC
> On Mon, 2 Jun 2008 13:51:18 -0500 "James Whitfield" <n5gui at cox.net>
> writes:
> > Bob
> >
> > You did not say if you were trying to mount an LED ( presumably a 1
> > Watt or
> > 3 Watt version ) in a standard bicycle headlamp fixture, or if you
> > are
> > "starting sorta' from scratch".
> >
> > If you are trying to put an LED into an existing fixture that will
> > take a
> > standard size flashlight bulb, then you might look into the
> > "replacement"
> > versions that are sold in hardware stores. That may just drop in.
> >
> > If you can tolerate a rather mechanically awkward solution, mount a
> > three-"C" or three-"D" cell flashlight, such as the Mag-Lite, which
> > has an
> > adjustable focus by twisting the head. The reflector in the head is
> > a
> > paraboloid which will focus parallel rays to a point, or conversly
> > direct
> > rays from a point source into parallel rays ( seen as a "spot" ).
> > The
> > filiment of a flashlight bulb is usually smaller than an LED
> > emitter, thus
> > closer to a point source, and therefore procduces a tighter spot of
> > light.
> > By moving the source forward or aft of the focus, the minimum spot
> > size gets
> > bigger.
> >
> > This may be closer to what you have in mind for a bicycle headlamp:
> > I have
> > tried to mount an LED from a string of Christmas Tree lights in the
> > focus of
> > a 6V lantern flashlight. The LEDs that I am using have a inverted
> > conical
> > tip to make a more spherical pattern than other LEDs. What you
> > might try is
> > mounting the high power LED just aft of the focus. You probably
> > will have
> > to cut off the back of the reflector because the hole for a
> > flashlight bulb
> > isn't big enough. The reflector was designed for flashlight bulbs
> > with the
> > filament ( point source ) forward and having some light emitted at
> > a
> > rearward angle. That "rearward" part of the reflector can be cut
> > off if
> > necessary to accomodate the larger LED assembly, which will emit
> > only
> > forward.
> >
> > Let us know how your project works out. It seems like it might be
> > applicable to "searchlight" beam for light communication. Maybe not
> > so far
> > off topic as you think.
> >
> > James
> > n5gui
> > ----- Original Message -----
> > From: <riese-k3djc at juno.com>
> > To: <Laser at mailman.qth.net>
> > Sent: Monday, June 02, 2008 11:27 AM
> > Subject: [Laser] off topic
> >
> >
> > > any thoughts on how to use the higher powered leds as a bike
> > headlamp
> > > would like to be able to broaden the ilumination to make it less
> > of a
> > > spot light
> > >
> > > bob k3djc
> > > _______________________________________________
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> > >
> >
> >
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